A Make-At-Home Comet Recipe
(Dennis Schatz, Pacific Science Center, Seattle, WA)
    2 cups water  
    2 cups crushed dry ice (frozen carbon dioxide) 
    2 spoonfuls of sand/dirt 
    dash of ammonia (NH3) 
    drop of organic material (corn syrup)

Combine all ingredients, except the dry ice, in a pail 
lined with heavy plastic.  Use a wooden spoon to mix 
all ingredients.  

Wearing gloves, add the dry ice and stir until the 
mixture becomes stiff.  Carefully lift the plastic by 
the corners and squeeze almost closed just above the 
comet.  Using two hands (thus more than one person 
is needed), carefully, but forcefully form the comet 
into a ball through the plastic. 

Place on table and unwrap the newborn comet.  

Yield: One 15-cm cometary nucleus.


(Photo: National Optical Astronomy Observatory)